CLAIM
WHO coronavirus PCR test primer sequence is found in all human DNA; this means that the WHO test kits should find a positive result in all humans
DETAILS
Fails to grasp significance of observation: In order for the PCR amplification process to begin, it is essential for both primers to flank the same target sequence. Having only a single primer that binds to a sequence does not lead to amplification and produces a negative test result.Flawed reasoning: If the SARS-CoV-2 RT-PCR test detected human DNA, then all tests would return a positive result. This is clearly contradicted by the fact that only about 9% of all tests administered in the U.S. have been positive.
KEY TAKE AWAY
The reverse-transcription PCR (RT-PCR) test is the method of choice for detecting SARS-CoV-2 in samples and is highly specific for the virus. For a PCR test to successfully amplify nucleic acids (DNA or RNA) in a sample, it is necessary for a pair of primers, which are short sequences of single-stranded nucleic acids that recognize and bind to a specific region of the genome, to flank the same target sequence. If only one primer in the pair is able to do so, amplification does not take place and the test would produce a negative result. Therefore, an RT-PCR test for SARS-CoV-2 which uses a primer that matches a human gene sequence would produce a negative result if only human DNA alone were present.
REVIEW A blog post claiming that the SARS-CoV-2 nucleic acid test would give positive results for every test because it also identifies human DNA was published in April 2020 and has received more than 13,000 interactions on Facebook and other social media platforms like Reddit, according to social media analytics tool CrowdTangle. While it was published several months ago, the article has seen a resurgence of interest on social media in August 2020.
Claims calling into question the nucleic acid tests used to detect SARS-CoV-2 are not new; Health Feedback also reviewed a related claim that the PCR test would detect other coronaviruses and found it to be false, as the test is highly specific and does not detect genetic material from other coronaviruses.
The Piece of Mindful blog post takes a different tack from the earlier claim by citing the protocol of a SARS-CoV-2 nucleic acid test developed at the Pasteur Institute in Paris, which is available on the website of the World Health Organization. The protocol lists the nucleotide sequences of various primers used in the test. According to the blog post, the sequence of one primer matches that of a sequence found on the human chromosome 8 and because of this, the post claims that the test would also detect human DNA, thereby giving false-positive results. As we explain below, this claim stems from a fundamental misunderstanding of how PCR works.
The laboratory technique known as PCR, or polymerase chain reaction, is a widely-used technique in laboratories worldwide that was invented by Kary Mullis, who received the 1993 Nobel Prize in Chemistry for this work. PCR is used to make many copies of a particular segment of nucleic acid (DNA/RNA), a process known as amplification, which enables scientists to detect tiny amounts of nucleic acid in a sample (see animation video by Cold Spring Harbor Laboratorys DNA Learning Center below).
The method of choice for detecting SARS-CoV-2 in most countries is a variant of PCR which detects RNA, called reverse transcription PCR (RT-PCR) (SARS-CoV-2 is an RNA virus).
Our knowledge of the SARS-CoV-2 genetic sequence allows us to design primers that specifically bind to sequences that are unique to the virus, based on the principle of complementary base pairing. These primers are required to start the amplification process. In the protocol, the primers in question detect the presence of the gene sequence for RNA-dependent RNA polymerase (RdRp), which encodes an enzyme that is needed to make more copies of the viral genome[1].
However, primers act in pairs. In order to begin the amplification process, it is essential for both the forward and reverse primers to bind/anneal and flank the same target sequence. Although the sequence CTCCCTTTGTTGTGTTGT which matches the reverse primer also exists on the human chromosome 8, the forward primer listed in the protocol (ATGAGCTTAGTCCTGTTG) does not bind to any sequence on chromosome 8. We demonstrate this below by using the Basic Local Alignment Search Tool (BLAST), developed by the U.S. National Center for Biotechnology Information, to align the forward primer listed in the protocol with the human genome.
As we can see from the alignment results, none of the sequences among the top matches in the list, which are partial matches, can be found on chromosome 8:
In summary, although the sequence CTCCCTTTGTTGTGTTGT is present in the human chromosome 8, only one of the primers is able to recognize this sequence, which would produce a negative result if only human DNA was present. Therefore the claim that the PCR test would produce a false-positive result due to human DNAand the implication that the number of positive SARS-CoV-2 test results is artificially inflatedis incorrect and misleading. Furthermore, it is evident from testing statistics that not all tests produce positive results; according to the U.S. Centers for Disease Control and Preventions COVID Data Tracker, only 9% of all tests conducted in the U.S. are positive as of 30 August 2020, as Lead Stories pointed out in their fact-check of the same blog post:
Read this article:
Human DNA alone does not produce a positive result on the RT-PCR test for SARS-CoV-2 - Health Feedback
- The complete plastome sequences of invasive weed Parthenium hysterophorus: genome organization, evolutionary ... - Nature.com - February 18th, 2024 [February 18th, 2024]
- Multi-omic profiling reveals associations between the gut microbiome, host genome and transcriptome in patients with ... - Journal of Translational... - February 18th, 2024 [February 18th, 2024]
- Polymerase Chain Reaction (PCR) - National Human Genome Research Institute - February 18th, 2024 [February 18th, 2024]
- Genomic Time Machine Reveals Secrets of Human DNA - SciTechDaily - February 18th, 2024 [February 18th, 2024]
- 1 Million Unannotated Exons Discovered in the Human Genome - Technology Networks - February 18th, 2024 [February 18th, 2024]
- Hope for the night parrot: bird's full genome has been sequenced - Cosmos - February 18th, 2024 [February 18th, 2024]
- RevIT AAV Enhancer: Rev-up AAV genome production in upstream manufacturing - BioProcess Insider - February 18th, 2024 [February 18th, 2024]
- Multi-omics resources for the Australian southern stuttering frog (Mixophyes australis) reveal assorted antimicrobial ... - Nature.com - February 18th, 2024 [February 18th, 2024]
- Large-scale gene expression alterations introduced by structural variation drive morphotype diversification in Brassica ... - Nature.com - February 18th, 2024 [February 18th, 2024]
- Near-gapless and haplotype-resolved apple genomes provide insights into the genetic basis of rootstock-induced ... - Nature.com - February 18th, 2024 [February 18th, 2024]
- Secrets of Night Parrot unlocked after first genome sequenced - CSIRO - February 18th, 2024 [February 18th, 2024]
- CRISPR gene editing tool gets a revolutionary high-tech upgrade - Earth.com - February 18th, 2024 [February 18th, 2024]
- Ancient retroviruses played a key role in the evolution of vertebrate brains - EurekAlert - February 18th, 2024 [February 18th, 2024]
- Natural selection and genetic diversity maintenance in a parasitic wasp during continuous biological control application - Nature.com - February 18th, 2024 [February 18th, 2024]
- Hopes elusive parrots genome will provide answers - news.com.au - February 18th, 2024 [February 18th, 2024]
- MicroRNA is the master regulator of the genome researchers are learning how to treat disease by harnessing the ... - The Conversation - November 30th, 2023 [November 30th, 2023]
- "Ground-Breaking" Release of World's Largest Whole Genome Resource - Inside Precision Medicine - November 30th, 2023 [November 30th, 2023]
- Pangenome analysis reveals genomic variations associated with domestication traits in broomcorn millet - Nature.com - November 30th, 2023 [November 30th, 2023]
- Global genetic diversity, introgression, and evolutionary adaptation of indicine cattle revealed by whole genome ... - Nature.com - November 30th, 2023 [November 30th, 2023]
- Genome characteristics of atypical porcine pestivirus from abortion cases in Shandong Province, China - Virology Journal - Virology Journal - November 30th, 2023 [November 30th, 2023]
- Correcting modification-mediated errors in nanopore sequencing by nucleotide demodification and reference-based ... - Nature.com - November 30th, 2023 [November 30th, 2023]
- CRISPR-Based "Genome Shredding" Technique Shows Promise in Treating Glioblastoma - Inside Precision Medicine - November 30th, 2023 [November 30th, 2023]
- Genome wide analysis revealed conserved domains involved in the effector discrimination of bacterial type VI secretion ... - Nature.com - November 30th, 2023 [November 30th, 2023]
- TRISH to investigate the effects of spaceflight on the human genome, central nervous system - Odessa American - November 30th, 2023 [November 30th, 2023]
- The venom preceded the stinger: Genomic studies shed light on the origins of bee venom - EurekAlert - November 30th, 2023 [November 30th, 2023]
- Integrating genomic and multiomic data for Angelica sinensis provides insights into the evolution and biosynthesis of ... - Nature.com - November 30th, 2023 [November 30th, 2023]
- Genetic diversity and ancestry of the Khmuic-speaking ethnic groups ... - Nature.com - September 21st, 2023 [September 21st, 2023]
- Researchers to Apply Genome Analysis to Childhood Cancers; Goal ... - The Japan News - September 21st, 2023 [September 21st, 2023]
- How Bats' Genomes May Help Them Avoid Cancer and Survive ... - Technology Networks - September 21st, 2023 [September 21st, 2023]
- Longitudinal genomic surveillance of carriage and transmission of ... - Nature.com - September 21st, 2023 [September 21st, 2023]
- Whole genomes from bacteria collected at diagnostic units around ... - Nature.com - September 21st, 2023 [September 21st, 2023]
- Genome-wide identification of lncRNA & mRNA for T2DM | PGPM - Dove Medical Press - September 21st, 2023 [September 21st, 2023]
- Tasmanian tiger RNA is first to be recovered from an extinct animal - Nature.com - September 21st, 2023 [September 21st, 2023]
- Loneliness and depression: bidirectional mendelian randomization ... - Nature.com - September 21st, 2023 [September 21st, 2023]
- Rome Therapeutics adds $72 million to Series B round to harness ... - OutSourcing-Pharma.com - September 21st, 2023 [September 21st, 2023]
- Mystery of 'living fossil' tree frozen in time for 66 million years finally ... - Livescience.com - September 21st, 2023 [September 21st, 2023]
- Why the human genome could be healthcares holy grail - Yahoo Finance - May 4th, 2023 [May 4th, 2023]
- Scientists Compare Genomes of 240 Mammals to Understand Human DNA - The New York Times - May 4th, 2023 [May 4th, 2023]
- Genomes From 240 Mammalian Species Help Explain 100 Years Of Evolution And Human Disease - ABP Live - May 4th, 2023 [May 4th, 2023]
- 'Deletions' from the human genome may be what made us human - Yale News - May 4th, 2023 [May 4th, 2023]
- GeneDx Adds Buccal Swab as Non-Invasive Whole Genome ... - GlobeNewswire - May 4th, 2023 [May 4th, 2023]
- Whole-genome sequencing used to track down genes behind familial glioma - Medical Xpress - May 4th, 2023 [May 4th, 2023]
- Wiggly proteins guard the genome: Dynamic network in the pores of ... - Science Daily - May 4th, 2023 [May 4th, 2023]
- Genome-Wide Splicing Quantitative Expression Locus Analysis ... - Cancer Discovery - May 4th, 2023 [May 4th, 2023]
- Digital Genome Market is expand at a CAGR of 8.6% to reach USD ... - Digital Journal - May 4th, 2023 [May 4th, 2023]
- High School Students Learn the Basics of Base Editing to Cure GFP ... - University of California San Diego - May 4th, 2023 [May 4th, 2023]
- Genomic researchers gain access to CSIRO's AI-powered data ... - Microsoft - May 4th, 2023 [May 4th, 2023]
- Archaic hominin traits through the splicing lens - Nature.com - May 4th, 2023 [May 4th, 2023]
- Critical bug in genome sequencing device scores '10' on CVSS ratings - SC Media - May 4th, 2023 [May 4th, 2023]
- Novel Genomic Approach Ensures Better Diagnosis of Hereditary ... - Technology Networks - May 4th, 2023 [May 4th, 2023]
- Intellia Therapeutics: Leading the Way in Revolutionary Genome ... - Best Stocks - May 4th, 2023 [May 4th, 2023]
- Visual tracking of viral infection dynamics reveals the synergistic ... - Nature.com - May 4th, 2023 [May 4th, 2023]
- Genome | Genome LLC | United States - March 31st, 2023 [March 31st, 2023]
- Belarus: EU and WHO deliver equipment for research of genomes of infectious disease agents - EIN News - February 24th, 2023 [February 24th, 2023]
- Gene vs. genome: Definition, function, and impact - January 30th, 2023 [January 30th, 2023]
- Big cog in the wheel: As Covid worries reappear, Insacogs genome sequencing ability must be aided by govts - Times of India - December 25th, 2022 [December 25th, 2022]
- CapitalGainsReport Sector Spotlight: Healthcare Penny Stocks On The Move (ARDX, WHSI, BNGO) - Marketscreener.com - November 25th, 2022 [November 25th, 2022]
- Genome Insight and Kun-hee Lee Child Cancer & Rare Disease Project Team of SNUH (Seoul National University Hospital) Made an Agreement About a... - November 23rd, 2022 [November 23rd, 2022]
- Genome-wide association study reveals distinct genetic associations related to leaf hair density in two lineages of wheat-wild relative Aegilops... - October 19th, 2022 [October 19th, 2022]
- The Global Genomics Market to Exhibit Growth at a CAGR of 16.90% During the Forecast Period (20222027) | DelveInsight - Yahoo Finance - October 19th, 2022 [October 19th, 2022]
- Illumina and GenoScreen Partner to Expand Access to Genomic Testing for Multidrug-Resistant Tuberculosis - PR Newswire - October 19th, 2022 [October 19th, 2022]
- Superresolution Method Poised to Better Gene Function Understanding - Photonics.com - October 19th, 2022 [October 19th, 2022]
- Genome-centric analysis of short and long read metagenomes reveals uncharacterized microbiome diversity in Southeast Asians - Nature.com - October 15th, 2022 [October 15th, 2022]
- How a New Battery Data Genome Project Will Use Vast Amounts of Information to Build Better EVs - InsideClimate News - October 15th, 2022 [October 15th, 2022]
- Scientists Reconstruct the Genome of the 180-Million-Year-Old Common Ancestor of All Mammals - SciTechDaily - October 15th, 2022 [October 15th, 2022]
- Combining OSMAC, metabolomic and genomic methods for the production and annotation of halogenated azaphilones and ilicicolins in termite symbiotic... - October 15th, 2022 [October 15th, 2022]
- Concerted expansion and contraction of immune receptor gene repertoires in plant genomes - Nature.com - October 15th, 2022 [October 15th, 2022]
- Uncovering the Full Variant Continuum with Pioneering Solutions from Bionano - Inside Precision Medicine - October 15th, 2022 [October 15th, 2022]
- Metagenomic analysis of viromes in tissues of wild Qinghai vole from the eastern Tibetan Plateau | Scientific Reports - Nature.com - October 15th, 2022 [October 15th, 2022]
- Research Assistant in Molecular and Genome Editing Therapeutics job with KINGS COLLEGE LONDON | 311876 - Times Higher Education - October 15th, 2022 [October 15th, 2022]
- Lessons learnt from COVID-19 shed light on future pandemic preparedness - The Peter Doherty Institute for Infection and Immunity - October 15th, 2022 [October 15th, 2022]
- From Neanderthal genome to Nobel prize: meet geneticist Svante Pbo - Nature.com - October 8th, 2022 [October 8th, 2022]
- Revealing the genome organization of the earliest common ancestor of all mammals - Tech Explorist - October 8th, 2022 [October 8th, 2022]
- Mitochondrial DNA Is Working Its Way Into the Human Genome - Technology Networks - October 8th, 2022 [October 8th, 2022]
- Animated Map: Where to Find Water on Mars - Visual Capitalist - October 8th, 2022 [October 8th, 2022]
- Reconstruction of The First Mammal's Genome Suggests It Had 38 Chromosomes - ScienceAlert - October 6th, 2022 [October 6th, 2022]
- Genomic Science Breakthroughs Are Happening Faster Than Ever Thanks to HPC - CIO - October 6th, 2022 [October 6th, 2022]
- Genome Of Ancient Humans Is The Winning Field Of 2022's Nobel Prize in Medicine - IFLScience - October 6th, 2022 [October 6th, 2022]
- ASU professor to study new genome editing tools with NIH Innovator Award - ASU News Now - October 6th, 2022 [October 6th, 2022]
- New R&D norms to fast-track research on genome-edited crops - The Financial Express - October 6th, 2022 [October 6th, 2022]